Many of the production processes used to produce fine particulate or powdered material, such as, for example, toner for use in electrophotographic printing and/or copying machines, are carried out in a controlled environment. The controlled environment typically includes a vessel or container within which the fine particulate or powdered material is contained, and within which a production process, such as, for example, sifting or milling, occurs. A flow of pressurized gas, such as, for example, air, nitrogen or other inert gas, is typically provided to the interior of the vessel or container. The flow of pressurized gas serves various purposes, including the control of dust, facilitating the movement or flow of material, reducing the entry of contaminants into the vessel or container, and reducing the possibility of explosion. An exhaust flow path is typically provided for controlled venting of the pressurized gas from the vessel. The flow of exhaust gas may be captured, used in other processes and/or recycled.
A certain amount of the particulate or powdered material is picked up by the flow of pressurized gas and carried into the exhaust flow path. Depending upon the characteristics of the particulate or powdered material, the exhaust gas flow may consist of from approximately 2 to 5 percent or higher of the particulate or powdered material. The particulate or powdered material accumulates in the exhaust flow path or portions thereof. The exhaust flow path or exhaust ducting must therefore be cleaned periodically to remove the accumulated particulate or powdered material.
One or more filters may be disposed within the exhaust flow path or exhaust ducting to remove the particulate material from the flow of exhaust gas. The fine particulate, or powdered material, is trapped by the filters; thereby making the exhaust gas, substantially cleaner and more environmentally benign. The filters, however, require a significant amount of maintenance. Preventative maintenance, such as cleaning and/or replacement of the filters, must be performed periodically. Although such periodic preventative maintenance occurs on a reasonably predictable basis, it nonetheless requires suspension of the production process. Such downtime in a production process is costly and undesirable. Further, filters may become clogged or tear and thus may require maintenance and result in downtime of a less predictable nature. Such tears may also result in an undesirable venting of particulate material into the manufacturing plant and/or the outside environment.
It is desirable to recycle the particulate material captured by the filters. Conventionally, this is done by cleaning the filters, to thereby collect the particulate material captured therein. The collected particulate material is then manually returned to a downstream point in the production process. The manual nature of cleaning the filters, collecting the captured particulate material and returning it to the production process can be relatively time consuming and labor intensive. Cleaning the filters and returning the captured material to the production process also requires suspension of the production process and, thus, even more downtime.
Therefore, what is needed in the art is a method and apparatus for removing fine particulate or powdered material from a flow of gas that reduces the need for manually cleaning of filters.
Furthermore, what is needed in the art is a method and apparatus for removing fine particulate or powdered material from a flow of gas that automates the filter cleaning process.
Still further, what is needed in the art is a method and apparatus for removing fine particulate or powdered material from a flow of gas that automates the process of recycling the material captured by the filter.
Yet further, what is needed in the art is a method and apparatus for removing fine particulate or powdered material from a flow of gas that reduces the downtime required for preventative and other maintenance.
Moreover, what is needed in the art is a method and apparatus for removing fine particulate or powdered material from a flow of gas that reduces the likelihood that particulate matter may be undesirably vented to the environment.